The deep structure of the North Anatolian Fault Zone

Fichtner, Andreas; Saygin, Erdinc; Taymaz, Tuncay; Cupillard, Paul; Capdeville, Yann; Trampert, Jeannot

doi:10.1016/j.epsl.2013.04.027

Cited by 150 publications

(141 citation statements)

References 48 publications

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“…The latest tool for assimilating this information into seismic velocity models is fully three-dimensional (3-D) waveform tomography [e.g., Tarantola, 1988;Tromp et al, 2005;Chen et al, 2007aChen et al, , 2007bBen Hadj Ali et al, 2009a, 2009bChen, 2011;Fichtner, 2011;Lekic and Romanowicz, 2011;Liu and Gu, 2012;Colli et al, 2013;Fichtner et al, 2013;French et al, 2013;Prieux et al, 2013;Schiemenz and Igel, 2013]. Full-3-D tomography (F3DT) accounts for the physics of wave excitation and propagation by numerically solving the inhomogeneous equations of motion for a heterogeneous, anelastic solid [Olsen et al, 1995;Komatitsch and Tromp, 1999;Cui et al, 2010;Peter et al, 2011].…”

Section: Introductionmentioning

confidence: 99%

Full‐3‐D tomography for crustal structure in Southern California based on the scattering‐integral and the adjoint‐wavefield methods

et al. 2014

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We have successfully applied full-3-D tomography (F3DT) based on a combination of the scattering-integral method (SI-F3DT) and the adjoint-wavefield method (AW-F3DT) to iteratively improve a 3-D starting model, the Southern California Earthquake Center (SCEC) Community Velocity Model version 4.0 (CVM-S4). In F3DT, the sensitivity (Fréchet) kernels are computed using numerical solutions of the 3-D elastodynamic equation and the nonlinearity of the structural inversion problem is accounted for through an iterative tomographic navigation process. More than half-a-million misfit measurements made on about 38,000 earthquake seismograms and 12,000 ambient-noise correlagrams have been assimilated into our inversion. After 26 F3DT iterations, synthetic seismograms computed using our latest model, CVM-S4.26, show substantially better fit to observed seismograms at frequencies below 0.2 Hz than those computed using our 3-D starting model CVM-S4 and the other SCEC CVM, CVM-H11.9, which was improved through 16 iterations of AW-F3DT. CVM-S4.26 has revealed strong crustal heterogeneities throughout Southern California, some of which are completely missing in CVM-S4 and CVM-H11.9 but exist in models obtained from previous crustal-scale 2-D active-source refraction tomography models. At shallow depths, our model shows strong correlation with sedimentary basins and reveals velocity contrasts across major mapped strike-slip and dip-slip faults. At middle to lower crustal depths, structural features in our model may provide new insights into regional tectonics. When combined with physics-based seismic hazard analysis tools, we expect our model to provide more accurate estimates of seismic hazards in Southern California.

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Section: Introductionmentioning

confidence: 99%

Full‐3‐D tomography for crustal structure in Southern California based on the scattering‐integral and the adjoint‐wavefield methods

et al. 2014

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“…The slow velocity anomaly was attributed to the ascending asthenosphere that is emplaced beneath the plateau following the detachment of the northward-subducting Arabian oceanic lithosphere (Keskin, 2003;Faccenna, 2003;Şengör et al, 2003;Biryol et al, 2011;Fichtner et al, 2013a, b). Recently, tomography studies by Biryol et al (2011) andFichtner et al (2013a) have confirmed that a hot and buoyant asthenospheric body supports the ∼ 2 km elevation of the Eastern Anatolian Plateau in the presence of an about 45 km thick crust (Şengör et al, 2003;Zor et al, 2003). At about 350 km depth, a fast anomaly has been found by tomographic studies and interpreted to represent a slab detachment (Lei and Zhao, 2007;Zor, 2008 Kalafat et al, 2008), NOA-Net, Aristotle University Thessaloniki (HT-Net) and GEOFON (Hanka and Kind, 1994;GEOFON Data Centre, 1993).…”

Section: Introductionmentioning

confidence: 99%

Thickness of the lithosphere beneath Turkey and surroundings from S-receiver functions

et al. 2015

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Abstract. We analyze S-receiver functions to investigate variations of lithospheric thickness below the entire region of Turkey and surrounding areas. The teleseismic data used here have been compiled combining all permanent seismic stations which are open to public access. We obtained almost 12 000 S-receiver function traces characterizing the seismic discontinuities between the Moho and the discontinuity at 410 km depth. Common-conversion-point stacks yield wellconstrained images of the Moho and of the lithosphereasthenosphere boundary (LAB). Results from previous studies suggesting shallow LAB depths between 80 and 100 km are confirmed in the entire region outside the subduction zones. We did not observe changes in LAB depths across the North and East Anatolian faults. To the east of Cyprus, we see indications of the Arabian LAB. The African plate is observed down to about 150 km depth subducting to the north and east between the Aegean and Cyprus with a tear at Cyprus. We also observed the discontinuity at 410 km depth and a negative discontinuity above the 410, which might indicate a zone of partial melt above this discontinuity.

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“…This is much less than the 100-125 km thickness of the cold and stable mantle lithosphere in the Arabian Shield and Iranian Plateau (e.g., Angus et al, 2006). Consequently, delamination and slab break-off models have been proposed to explain the thin lithosphere (e.g., Al-Lazki et al, 2003;Gök et al, 2003;Keskin, 2003;Şengör et al, 2003;Faccenna et al, 2006;Lei and Zhao, 2007;Göğüş and Pysklywec, 2008;Toksöz et al, 2010;Biryol et al, 2011;Koulakov, 2011;Fichtner et al, 2013;Bartol and Govers, 2014). The rapid topographic uplift in Eastern Anatolia between the late Miocene and early Pliocene might be attributed to the dynamic and isostatic effects of delamination, slab break-off, and a compressional regime between the Arabian and Eurasian plates (Keskin, 2003;Şengör et al, 2003;Faccenna et al, 2006;Göğüş and Pysklywec, 2008).…”

Section: Introductionmentioning

confidence: 99%

Lithospheric structure and the isostatic state of Eastern Anatolia: Insight from gravity data modelling

2018

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Eastern Anatolia, Turkey, is a part of the Alpine-Himalayan collisional belt where continental crust is relatively thin for a collisional belt. The region contains part of the Zagros suture zone, which formed during collision of the Arabian and Anatolian plates in the Miocene. It is underlain by a low-velocity zone associated with asthenospheric flow in the uppermost mantle.We constructed gravity models of the crust and upper-mantle structures to assess the driving mechanism of asthenospheric flow and the isostatic state of Eastern Anatolia. Our density models are based on terrestrial and satellite-derived gravity data, and they are constrained by receiver function and seismic tomography. The gravity models show significant lithospheric thickness variations across the Anatolian and Arabian plates. The lithospheric mantle in Eastern Anatolia is thinner (~62-74 km) than the Arabian plate (~84-95 km), indicating that part of the Anatolian mantle lithosphere might have been removed by delamination. The lithospheric removal process might have occurred following the detachment of the Arabian slab in the Miocene. Widespread Holocene volcanism and high heat flow in Eastern Anatolia can be considered as evidence of lithospheric delamination and slab break-off. The upward asthenospheric flow and subsequent asthenospheric underplating beneath Eastern Anatolia might have been induced by both delamination and slab break-off. These two processes may account for the rapid uplift of the Anatolian Plateau. There is a residual topography of ~1.7 km that cannot be explained by crustal roots. Based on our gravity models, we suggest that part of the eastern Anatolian Plateau is dynamically supported by asthenospheric flow in the upper mantle.

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The deep structure of the North Anatolian Fault Zone

Cited by 150 publications

References 48 publications

Full‐3‐D tomography for crustal structure in Southern California based on the scattering‐integral and the adjoint‐wavefield methods

Full‐3‐D tomography for crustal structure in Southern California based on the scattering‐integral and the adjoint‐wavefield methods

Thickness of the lithosphere beneath Turkey and surroundings from S-receiver functions

Lithospheric structure and the isostatic state of Eastern Anatolia: Insight from gravity data modelling

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